1. Field of the Invention
The present invention relates to a laminated structure formed of thin plates, and more particularly, to a laminated structure formed of thin plates in which a plurality of thin plate members are arranged in layers and bonded together by means of adhesive.
2. Description of the Related Art
In a print head installed in an inkjet recording apparatus (inkjet printer), a three-dimensional structure is formed by layering together a plurality of thin plate members (cavity plates), to a high degree of accuracy. For example, a thin plate member formed with a plurality of nozzle openings, and thin plate members formed with pressure chambers provided for the respective nozzles, openings, recesses, projections, and holes corresponding to ink flow channels, and the like, are arranged in layers and bonded together by means of adhesive material or adhesive sheet.
A thermosetting adhesive which can be hardened by means of heat, or an ultraviolet-setting adhesive which can be hardened by irradiating ultraviolet radiation, is used as the adhesive for bonding these thin plate members. Moreover, various methods have been devised for ensuring prescribed rigidity, strength and adhesive performance.
The adhesive is uniformly applied onto at least one of the surfaces that are to be bonded together (bonding surfaces) in a thin layer by means of a coating apparatus, or the like, but surplus adhesive may arise. A method is known in which escape grooves for adhesive and air bubbles are provided in such a manner that this surplus adhesive does not block up the openings, and the like, formed in the thin plate members, or in such a manner that no air bubbles are left between the thin plate members bonded together. These escape grooves should communicate with the outside air, in order that the adhesive and air bubbles can escape efficiently.
Japanese Patent Application Publication No. 2002-96478 discloses a laminated and bonded construction of thin plate parts, in which through holes communicating with adhesive escape grooves are provided, and these communicate with the outside air in the direction of the thickness of the thin plate parts, thereby allowing the air bubbles remaining between the plate parts to escape.
Japanese Patent Application Publication No. 2002-240272 discloses an inkjet printer, in which a structure is adopted wherein escape grooves are formed on only one of the surfaces to be bonded, thereby allowing the surplus adhesive to escape.
Japanese Patent Application Publication No. 2001-63052 discloses an ink-jet recording head and a method of manufacturing the inkjet recording head, in which a plurality of grooves are provided at intervals, and when plates formed with these grooves are bonded together, the grooves form linked grooves which communicate with the outside air, and the air bubbles remaining in the region of the plate junction can be made to escape into the outside air via these grooves.
However, in the case of a head of a long dimension in the lengthwise direction, such as a line head, if the grooves extend to the ends of the thin plate members, in such a manner that the two ends of the grooves in the breadthways direction parallel to the shorter edges of the head communicate with the outside air, then the rigidity of the thin plate members declines, and furthermore, the thin plate member may warp when the grooves are processed. There is also a possibility that the thin plate members may warp when the adhesive hardens. This decline in rigidity and the occurrence of warping in the thin plate members cause a decline in the performance of the head.
In the laminated and bonded construction of thin plate parts disclosed in Japanese Patent Application Publication No. 2002-96478, when a plurality of thin plate parts have been bonded together, air bubbles remaining in the sandwiched thin plate part cannot escape readily via the through holes provided in the thickness direction. Furthermore, the adhesive in the sandwiched thin plate part cannot escape readily either.
Moreover, in the inkjet printer disclosed in Japanese Patent Application Publication No. 2002-240272, no consideration is given to warping of the plates.
Furthermore, in the inkjet recording head and method of manufacturing the ink-jet recording head disclosed in Japanese Patent Application Publication No. 2001-63052, it is possible that the grooves may not link together, if the processing accuracy or bonding accuracy of the plates is low.